Cardiac Purkinje cells in culture.

Purkinje cells from false tendons of young rabbits, pigs and fetal lambs were dispersed by the action of collagenase and elastase and grown in culture for up to 14 days. Immunofluorescent staining with fluorescein-labelled antibodies to cardiac myosin and tropomyosin demonstrated cross-banding and/or a diffuse positive stain in Purkinje cells between 3 and 7 days in culture. Electron microscopy of cultured Purkinje cells at 3 days and 7 days revealed some disorganization of the myofilament system, in particular loss of Z-band material, as well as many thickened Z-bands, 120 nm to 240 nm in width. Gap junctions remained but desmosomes and fasciae adherentes were fewer in number. Organelles such as ribosomes, glycogen and mitochondria did not alter. Some Purkinje cells were spontaneously contractile in culture for up to seven days. Dominguez and Fozzard [7] propose that buckling of the Purkinje fibre and the production of sarcolemmal folds on the cell surface affect conduction of electrical impulses. We suggest that Purkinje cell contraction may play a major part in producing these geometric changes affecting conduction.